Waterbeds have become increasingly popular during the last few years. Generally, these beds comprise a watertight mattress filled with water and positioned within a rectangular frame on a suitable supporting surface. The frame itself has an appreciable width in a vertical direction so as to enclose the sides of the mattress.
When a person sits or lies on a waterbed, the water in the watertight mattress is displaced in such a manner that the person's body is neatly cradled by the mattress with substantially equal pressure applied to all contact areas. The displaced water, in turn, will exert substantial forces on the side and end boards making up the rectangular frame surrounding the mattress. In fact, the dynamic forces can greatly increase the normally present static force of water pressure exerted on the interior surfaces of the rectangular frame particularly if violent movements are made on the waterbed.
With the foregoing considerations in mind, it will be appreciated that the rectangular frame encircling the watertight mattress must be of substantial strength to properly confine the waterbed mattress itself to the normally desired overall rectangular shape.
Fairly thick and wide boards may be used in providing the waterbed frame. The problems arise, however, in securing the corners of these boards together to prevent separation under the extreme pressures of the water.
Suitable bracing has been, of course, provided in the past and is presently being used on waterbeds. However, such bracings as are available are generally expensive, very difficult and thus time consuming to install, and in many instances result in protrusions on the interior surface of the frame which could in turn puncture the mattress or exert undue pressure at certain points on the mattress.
One of the main factors in the cost of waterbeds is the labor time involved in assembling the frame and bed portion itself. Normally such assembly is done in the bedroom of a purchaser since the shipment of a mattress filled with water would be impractical. The time for such assembly as well as the integrity of the completed assembly will depend upon the skill of the installers. Both factors increase the cost of the waterbed if the assembly is to be done properly.